Process for the production of carbonyl groups in organic compounds



- water to produce diols.

The present ,invention relates to a process for the production ofcarbonyl groups in organic compounds containing one or more olefinicallyunsaturated double bonds and one or more heteroatoms, that is, atomsother than carbon and hydrogen. I

It is known that olefinic C=C- doublebonds can be converted oxidativelyby various reactions. For example,

- two hydroxyl groups can be introduced with potassium permanganate orosmiumtetroxide in the presence of When lead tetracetate is used twoacetoxy groups are introduced which secondarily can .be saponified tohydroxyl groups. It is furthermore known 7 that compounds containingolefinic C=C double bonds can be converted to olefine oxides with theaid of ele-. mental oxygen in thepresence of silver catalysts or withpercarboxylic acids. By hydrolysis and oxidation, such oxidationproducts can be converted to carbonyl com- United States Patent O poundscontaining aldehyde or keto groups in place of the olefinic double bondspreviously contained in such compounds. 7

In a similar manner, an olefinic C=C- double bond can be converted to aketo or aldehyde group, for example, by an addition reaction with acids,saponification of the resulting ester and subsequent oxidation of theresulting hydroxy group. I

I 'All of these processes require several reaction steps and closecontrol of the reaction conditions. Furthermore, they are often subjectto strong side reactions.

In co-pending applications Serial No. 738,040, filed December 27, 1957,now abandoned, and Serial No. 744,011, filed June 23, 1958,,now PatentNo. 3,080,425,

' processes are described for the production of carbonyl compounds fromolefinically unsaturated hydrocarbons in which such hydrocarbons areconverted with aqueous solutions of platinum group metal'compounds. Suchconversion also can be carried out in the presence of oxidizing agents.

According to the present invention it was found that such organiccompounds which in addition to one or more olefinicaily unsaturateddouble bonds also contains one or more heteroatorns (atoms otherthancarbon and hydrogen) can be reacted in a similar manner to producecarbonyl compounds with the aid of aqueous solutions of platinum groupmetal compounds. In the following,

' the simple reference to platinum metal compounds is emfployed to referto the platinum group metal compounds. Starting materialsfor the processaccording to the invention, for example, are olefinicallyunsaturatedcompounds containing oxygen,sulfur, halogens, nitrogen or silicon asgroups. Nitrogen, in addition to being bonded to carbon, can be bondedto hydrogen or oxygen. Silicon can be bonded directly to the organicportion of the compound or over oxygen. Of course, the startingcompounds employed according to the invention can contain severaldifferent heteroatoms.

In the process according to the invention the olefinically unsaturatedC= C- double bonds of aliphatic, aromatic or cyclic compounds containingone or more heteroatoms can be converted to aldehyde or ketone groupswithout splitting of the molecule at such location. When unstablecarbonylproducts are produced, the known secondary products areobtained. For example, in the introduction of a keto group in betaposition to a carboxyl group, a decarboxylation readily takes place. Thereaction according to the invention often will take place at ordinaryroom temperatures. However, it is expedient to employ temperaturesbetween C. and the boiling point or the reaction mixture. With the useof elevated pressures, temperatures up to 250 C. can be employed. Thereaction period required depends upon the starting compound and can varyfrom several minutes to a number of hours.

The process according to the invention can be carried out in a number ofways. The starting materials can be treated with aqueous solutions whichonly contain platinum metal compounds. It is, however, more economicalto employ solutions which in addition to small quantities of platinummetal compounds contain oxidizing agents in higher concentration.

The platinum metal compounds are catalytically active, particularly,thoseof palladium and rhodium. The type of the non-metallic component ofsuch compouudsis only of secondary importance as long as extremelystrongcornplex formers, such as cyanide ions, or precipitating agents,

such as sulfide ions, are not concerned. Usable platinum metalcompounds, for example, are the halides, sulfates,

" phosphates, acetates and correspondingcomplexes.

,heteroatoms. The type of linkage in which the hetero- 3 atoms-arepresent has no influence upon the courseof the reaction. Oxygen, forexample, can be present in the form of carbonyl, hydroxyl, ether, esteror carboxyl When oxidizing agents are employed in conjunction with i theplatinum metal compounds, their function is to compens'ate for or hindera reduction of the platinum metal compounds by the unsaturated organiccompounds. As a consequence, the oxidation potential of the oxidizingagents employed should be above that of the active platinum metalcompounds. ascertained in a known manner by electrical measure ments.Asa criterion, the tabulated values of normal potenti'alcan-be used.

NORMAL POTENTIALS OF OXIDIZING AGENTS (See 'Angew. Chemie 62, 3 19.)

' after separation from the reaction products and in the absence-oforganic starting compoundsby treatment with oxygen or with oxygen incombination with nitrogenoxyg en compounds, it is advantageous to usesalts of multivalent metals, especially of iron or copper, as theoxidizing agent. a

a The oxidizing agents insofar as they are soluble are employed togetherwith the platinum metal compounds in aqueous solution. Preferably theplatinum metal com pounds are employed in concentrations of 2 to 20 g.per liter and the oxidizing agent in higher concentrations. When saltsof multivalent metals are employed, ,a molar ratio of platinummetal to.multivalent metal of up to 1: and above can be employed. Halogen ionsretard The oxidation potential can be the reduction of solution but, onthe other hand, promote the oxidation with oxygen. Consequently, whenthe reaction is carried out with the use of oxygen and salts ofmultivalent metals, the-reaction can be controlled by the addition ofhalides, particularly chlorides. Preferably, a halogen ion concentrationis maintained which is 60 to 90% of the quantity which would becontained in the solution if all metals were present as halides in theirhighest stable oxidation step.

The reaction is carried out in acid to neutral solution. A pH of '0 to 2is preferred.

If the process is carried out with regeneration of the catalystsolution. with oxygen and nitrogen-oxygen compounds, it is advantageousto employ sulfate containing catalyst solutions. Ferric sulfate is.preferred. Nitrogen oxides and nitric acid are suited nitrogen-oxygencompounds. It is especially advantageous if an excess of oxidizingnitrogen-oxygen compound, with reference to reduced portions of thecatalyst solution in the part of the catalyst solution being reoxidized,is maintained in the oxygen and nitrogen-oxygen compound mixture employed for the reoxidation.

In order to attain usable oxidationefficiencies, it is neither necessaryto employ especially high concentrations of nitrogen-oxygen compounds orto employ stoichiometric, quantities of the nitrogen-oxygen compoundswith reference to the reduced portions of the entire catalyst solution.It is only essential that the nitrogen-oxygen compounds are alwayspresent in the 'portion of the catalyst solution being reoxidized inexcess of the reduced portions contained in such portion of catalystsolution. This, for example, can be achieved by adjusting the velocityat which the catalyst solution is supplied to the action of oxygen andnitrogen-oxygen compounds to a velocity corresponding to the progress ofthe oxidation. The continuous presence of sufficient quantities ofoxygen has the effect of maintaining the original quantity of oxidizingnitrogen-oxygen compounds supplied by continuous reformation of suchnitrogen-oxygen compounds during the reaction. It is therefore possiblein view of this constant regeneration of the nitrogen-oxygen compound tocarry out the regeneration of the catalyst solution with a quantity ofnitrogen-oxygen compounds which is considerably less than thestoichiometric quantity required for reoxidation of all of the reducedportions of the catalyst solution taken as a whole over a period of timeprovided suitable adjustment of the rate of supply of the used catalystsolution to the action of the oxygen and nitrogen-oxygen compounds ismaintained. Even when working under such conditions the reoxidation israpid and complete.

The treatment of the used catalyst solution with the oxygen andnitrogen-oxygen compounds can take place at ordinary room temperatures.It is, however, preferable to employ elevated temperatures, for example,in the range of 50 to 170 C. The pressures employed are selected withregard to the temperatures used. Pressures of, for example, 1 to 50atmospheres can be used.

The reoxidized catalyst solution is then admixedwith a small excess of afurther quantity of used catalyst solutionwith respect to the quantityof 'nitric acid or nitrogen-oxygen compounds still contained therein andpassed through a filled tower and treated with air or steam to free itfrom nitrogen oxides before being reused as the catalyst for theproduction of carbonyl compounds.

The process according to the invention involves a reaction betweenphases of only limited miscibility. As a consequence, all measures whichprovide for intensive intimate contact of the phases or increase themiscibility of the phases promote the reaction. Intensive contact can beattained by mechanical measures such as stirring, shaking, vibrating,spraying and the like and chemical measures which favor the formation oflarge surfaces. In

order to increase the miscibility, blending agents such as acetic acidor dioxane can be added. The solubility of gaseous reactants can beincreased by employing superatmospheric pressures. The process accordingto the invention can be carried out at any desired pressure, preferably,however, a pressure within the range of 1 to 50 atmospheres is employed.

The time during which the unsaturated organic compounds and the reactionproducts are in contact with the aqueous catalyst solution can amountfrom a few minutes to several hours. The time of contact depends uponreactivity ofstarting unsaturated compounds, the composition of thecatalyst solution, the pressure and temperature, as well as the type ofoxidizing agent'ernployed.

Y The lower strongly polar unsaturated organic compounds reactrelatively rapidly, whereasthe higher less polar or non-polar compoundsrequire longer reaction times. Palladium compounds act very quickly,Whereas the compounds of the other platinum metals are considerablyslower in their action. The influence of halogen ions has already beenmentioned. Increases in'pressure and temperature accelerate thereaction. An upper limit for the time of contact is provided in the caseof easily oxidizab'le and acid sensitive carbonyl compounds, especiallywhen higher temperatures are employed" and when strong oxidizing agentsare employed. The permissible periods of contact caneasily-be.determinedfor each individual case by determining the yields obtained.

The process accordingto the inventioncan be carried out in all apparatusfor reacting gases, liquids or solids with-each other, such as, forexample, trickle or spray towers, filled" columns, stirring vessels andthe like. Naturally, the portions ofsuch apparatus coming into contactwith the strong oxidizing acid' solutions must be of corrosion resistantmaterial. Suitable corrosion resistant materials, for example, areenamel, glass, porcelain, stoneware, synthetic resins, rubber, titanium,tantalum and Hastelloy. I l

The reactionproducts produced can be recovered in various ways. Easilyvolatilized compounds, insofar as they are carried outwith thenon-converted gas stream, can be separated out by condensation orscrubbing. The compounds retainedin the catalyst solution can berecovered by distillation. Di-fiicultly volatile compounds can berecovered-by liquid-liquid extraction, separation or filtration. t

The following examples-will serve to illustrate a number of embodimentsof the process according to the invention.

' EXAMPLE 1 106.7 g. of metallic palladium were dissolved in aqua regiaand this solution evaporated to dryness on a sand bath. The residue wastaken up in 200 cc. of 20% HCl and evaporated to dryness again. Thislatter procedure was repeated three times. A suflicient quantity of 1 nHCl was added to. the resulting nitrate free residue so that uponwarmingcomp-lete solution was afi'ected. After the solution cooledasufficient quantity of water was added to provide 5.335 liters-ofsolution and a small quantity of HCl' was added so that the solutioncontained 21' mg. HCl per cc. of solution. The resulting solutioncontained 20 mg. of palladium per cc. and was. used in the followingexamples. 7

0.1- rnol anethol (4-methoxy-I-propenyl-benzol) was shaken together with533 cc. of this palladium chloride solution (:01 mol palladium) for 4 /2hours at 70 C. pMethoxyphenyl acetone was obtained-as the reactionproduct in 91% of the theoretical yieldwith a 55% conversion. Themelting point and the mixed melting point of the2,4'-dinitrophenylhydrazone thereof was C. (:DNP hydrazone).

EXAMPLE 2 0.1 mol of crotonald'ehydewas mixed with 533 cc. of apalladium chloride solution (=0.1 mol palladium) prepared'as in Example1 and the mixture allowed to stand for 3 hours at 25 C. Acetylacetaldehyde was to 1,3,5-t1iacetylbenzol. The yield of triacetylbenzolwas 85% of the theoretical with a 35% conversion. The melting point andmixed melting point of the triacetyl- 6 EXAMPLE 7 15.5 g. ofrhodium-(IID-hydroxide (=01 mol rhodium) were dissolved in 200 cc. of 1n HCl. Suflicient water was added to provide 500 cc. of solution. 0.1

0.04 mol of cinnamic acid was mixed with 107 cc.

of a palladium chloride solution prepared as in Example 1 ('=0.02 molpalladium) to which 0.02 mol of ferric sulfate had been added and themixture shaken for 6 hours at 70 C. The test was repeated using doublethe quantity of palladium chloride solution (:0104 mol palladium) in theabsence of ferric sulfate. When the iron compound containing solutionwas employed, the conversion was 68% producing a yield of acetophenonewhich was 92% of the theoretical. In the absence of the iron compoundthe conversion was 70% and the yield 90% of the theoretical.

EXAMPLE 5 II 0.04 mol of cinnamic acid was mixed with 54 cc.

of a palladium chloride solution prepmed as in Example EXAMPLE 6 I I 0.1mol of cinnamic acid ethyl ester was mixed with 533 cc. of a palladiumchloride solution prepared as in Example 1 to which 100 cc. of dioxanehad been added and the mixture shaken for 5 hours at 70 C. A conversionof 66% with a'yield 91% of the theoretical of a'cetophenone wasobtained.

benzol was 163 C.

- 1 I 5 mol of cmnannc acid was added to this solutlon and tne I XA E 3mixture was shaken for 1 4 hours at 7 0 C. Acetophenone 0.1 mol of theunsaturated carboxylic acids'tested in was Obtamed. m a yleld 85% of thetheoreucalthe. following table WereLeach mixed with 533 cc. of a EXAMPLE8 palladium chloride solution prepared as in Example 1 10 and shaken forthe period and 'at the temperature in- 0.03 mol of3-chloro-2-methyl-propene-(l) was mixed dicated in the table. a a with17 0 cc. of a palladium chloride solution (=0.03 mol Table Temp, React.Conver- Yield, Starting Material C. Per. Product sion, percent percent(1. Th.

'. Acrylic acid; .1 50 I 180 Acetaldehyde 50 93 CHz=CH-COOH CHa-CHO YDNP, M.P. 166 7 Orotonic acid so so Acetoneflnl 91 OHa-CH=CH-COOHCHaOO-C13s DNP, M.P. 126 Methacrylic acid 40 120 Propionaldehyde 61 00OH=C-COOH I CHa-CHz-CHO i DNP, M.P. 147 CH3 Oinnamic acid 50 600Acetophcnone 92 CQH;.CH=CHCOOH Y C H5-COOH3 I I DNP, M.P. 244 I Maleicacid 50 180 Pyruvic acid 25 91 HOOC0H=OHGO0H GHa-COCOOH I DNP, M.P. 2177 Tiglie acid 50 120 Methylethylketone 40 95 QHSCH=C-CQO CHz- OCH2OH3 IDNP;M.P. 110 1 I I Itaconic aciaso Succinic aldehyde acid- 3'0 90HOOOOH2CCOOH OOHOHr-OHCOOH I DNP, M.1.207. I 0H2 I Sorbic acid I 65 15Ethylidene acetone 3s 92 CHr-(CH=OH)z-COOH CH3CH=CHCO-CH3 I DNP, M.i 156EXAMPLE 4 palladium) prepared as in Example 1 and the mixture shaken for1 hour at 50 C. Alpha methyl acrolein 5 was obtained as the reactionproduct in a yield of 85% of the theoretical.

I The melting point and mixed melting point of the DNP hydrazone thereofwas 198 C. (Z).

. EXAMPLE 9 EXAMPLE 10 0.03 mol of alpha chlorostyrene was mixed with170 cc. of a palladium chloride solution (=0.03 mol palladium) preparedas in Example 1 and the mixture shaken for 30 minutes at 40 CfAcetophenone was obtained as the reaction product in a yield of 88% ofthe theoretical. -The melting point and mixed melting point of the DNPhydrazonethereof was 273 C.

EXAMPLE 11 270 cc. of a palladium chloride solution (=0.05 molpalladium) prepared as in Example 1 were shaken together with 0.03 molof each of allylchloride, allylbromide and 2,3-dibromopropene-(1) for 30minutes in the case of the first two compounds and for 2 hours in thecase of the last compound at 50 C. In each instance methyl glyoxal wasthe reaction product. The yields were as follows: from allylchloride 65%of the theoretical; from allylbromlde 80% of the theoreticaland from2,3-dibromopropene-(1) 85% of the theoretical.

EXAMPLE 12 0.03 mol alpha-methyl acrylic acid amide was shaken togetherwith 170 cc. of a palladium chloride solution 0.03 mol palladium)prepared as in Example 1 for 2 hours at 50 C. Propionaldehyde wasobtained as the reaction product in a yield of 72% of the theoretical.The melting point and mixed melting point of the DNP hydrazone thereofwas 151 C.

EXAMPLE 13 0.03 mol of allylalc-ohol was shaken with 170 cc. ofapalladium chloride solution (=0.03 mol palladium) for 5 minutes at 25C. Acrolein was obtained as the reaction product in a yield of 75% ofthe theoretical. The melting point and mixed melting point of the DNPhydrazone thereof was 164 C. (Z).

EXAMPLE 15 0.03 mol of p-methoxystyrene was shaken with 170 cc. of apalladium chloride solution (=0.03 mol palladium) as prepared in Example1 for minutes at 20 C. addition to polymerized starting material,p-methoxyacetophenone was obtained in a yield of 45% of the theeretical. The melting point and mixed melting point of the DNP hydrazonethereof was 217 C.

Analogously a number of other unsaturated organic compounds were reactedwith an aqueous palladium chloride solution prepared as in Example 1.are given in the following table.

The results i We claim:

ing atleast one olefinically unsaturated bond and consisting of theatoms of hydrogen and carbon and at least one heteroatorn selected fromthe group consisting of oxygen, sulfur, chlorine, bromine and nitrogen,said heteroatom being in an acyclic linkage, to form a differentcompound containing a carbonyl group selected from the group consistingof aldehyde and keto carbonyl groups which comprises intimatelycontacting said compound containing at least one olefinicallyunsaturated bond with an aqueous solution of a platinum group rnetalsalt at a temperature of: above 0 C. to about 250 C.

2. The process of claim 1 in which said compound containing at least oneolefinically unsaturated bond contains at least one oxygen atom in theform of a carbonyl group.

3. The process of claim 1 in which" said compound containing at leastone olefinically unsaturated bond contains at least one oxygen atom inthe form of a hydroxyl group.

4. The process of claim 1 in which said compound containing at least oneolefinically unsaturated bond contains at least one oxygen atom in theformof an ether group.

5. The process of claim 1 in which said compound containing at least oneolefinically unsaturated bond contains at least one oxygen atom in theform of a carboxyl group.

6. The process of claim 1 in which said compound containing atleast oneolefinically unsaturated bond contains at least one nitrogen atom, inthe form of an amino group, bonded to a carbon atom of such compound.

. 7 The process of claim 1 in which said compound-containing at leastone olefinically unsaturated bond contains at least One nitrogenatom, inthe form of a nitro group, bondedtoa'carbon atom of suchcompound;

'8'. The process of claim 1 in which said salt is a palladium salt.

9. The process of claim 1 in which. said salt is arhodium salt.

10. The process of claim 1 in which said compound is Table 7 ReactionReaction Conver- Yield,

Starting Material Tcmpera- Time, Reaction Product sion 1 Percent ture,0. Minutes Iso-Satrol 70 120 3,4-dioxymethylencbenzylmethylketone.. 6991 a,e-P'cntenoic acid. 35 Ethylmcthylketone g8 92 a,fl-Hcxenoic acid 3570 n-Propylmethylketone; 94 95 a,fi-Heptenoic acid. 50n-Butylmethylkctone 36 91- a,fl-Octenoic acid 50 n-Amylmethylkctonc 9595 a-Methoxy-crotouic acid" 50 120 Acetone 82 90. Vinylbromide. 10 15Acetaldehyde 98 98 1-bromo-pr0pene- 30' 15 A cot nno 5 91l-bromo-butcnc-l 30 15 Ethylmethylketone 67' 95 1-bromo-pentcne 50 15n-Propylmethylketone. 61 92 1-bromo-hexenc-l 50 45 11-13 ntylmethyll 8895 l-bromo-hepteuc- 50 45 r ix-Ainylxmethyllietone 85 31 cc op enone A 0fl'Bromostyrene 40 20 {A t d 60 l 1 2-chloropropene-l 20 120 cetone 3238 a-Chloro-fl-mcthylstyrcne 70 120 Propiopheno 47 912-chloro-3-phenylpropene-1 70 1 10 Benzylmethylketone 25 922-chloro-1-phenylpropenc-1 70 l 10 Benzyl'methylkctone 22 92l-bromopenteneA 25 30 p-Bromopropylmethylketonc 53 94 p-Chlorostyrene.30 30 p-Chloroacetophenone 36 91 1,3'dichloropropene- 50 1 6Methylglyoxal 82 94 v a-Bromoacrylic acid 25 60 Acetaldehyde. 60 92a-Olilomcrotoni'c acid 50' 60 Acetone 76- 95- a-Bromo-afi-pentenoicacid. 50 60 Ethylmethylketone- 62' 93 u-Bromo-afl-hexenoic acid. 50 60n-Propylmethylketonc 57 94 a-Bromo-afl-heptehoic acid. 50 60nButyhnethylketonec 7O 91- a-Bromo-u.fl-octcnoic acid 50 60n-Amylmethylketouc. 65 91 a-Bromocmnamic aeidflo 60 Acetophenone (it 92-Ghlorocinnamic acid. 70 9 p-Ghloroacetophenone. 25littethacrylicacidamideu 50 30 Propionaldehyde 72 92 Crotonicacidamide50 30 Acetone 80' Y 91 afl-Pentenoic acid-amide. 50 30 Ehylmethylketonc. 71 9'2 Oirmamic acid amide 50 80 Acctopheuonc 48 91m-Nitrostyrene 50 m-Nitroacetophenoue 35 91 m-Nitrociunamlc acid amide-70 300 m-Nitro acetophenone 38 91 Allyl amine 25 15 Propionaldehyde 2588 Methyl-[buten-(D-yl-(4)lrsulphone 50 120Methyl-[butenon-(2)-yl-(4)]-sulphone 54 92 1 Hours.

intimately contacted with said aqueous salt solution in the 7 presenceof oxygen.

= 11. The process of claim 1 in Which said compound is intimatelycontacted with said aqueous salt solutionin the presence of an inertsolvent.

" 12. .The' process of claim 1 in which said aqueous salt solution has apH betWeen O and 2.

13. A process for the treatment of a compound containing at least oneolefinically unsaturated bond and consisting of the atoms of hydrogenandcarbon and at least one heteroatom selected from the group consistingof oxygen, sulfur, chlorine, bromine and nitrogen, said heteroatombeing'in an acyclic linkage, to form a different com pound containing acarbonyl group selected from the group consisting of aldehyde and ketocarbonyl groups which comprises intimately contacting said compoundcontaining at least one olefinically unsaturated bond with an aqueoussolution of a platinum group metal salt and an oxidizing agent having anoxidation potential above that of the platinum group metal salt selectedfrom the group consisting of water soluble copper and iron salts at atemperature of above 0 C. to about 250 C.

10 14. Theprocess of claim 13 in which the quantity of 'the firstmentioned salt in the aqueous solution is 2 to 20 grams per'liter ofsolution and theconcentration of the oxidizing agent in such solution isgreater than that of the 1 first mentioned salt.

15. The process of claim 13 in which said oxidizing agent is a ferricsalt.

References Cited in the file of this patent Phillips: Amer. Chem. Joun,volume 16, pages 255-77 (pages 261 and 265-72 relied upon) (1894).

Chatt: Chem. Abstracts, volume 48, page 5067 (1954).

1. A PROCESS FOR THE TREATMENT OF A COMPOUND CONTAINING AT LEAST ONEOLEFINICALLY UNSATURATED BOND AND CONSISTING OF THE ATOMS OF HYDROGENAND CARBON AND AT LEAST ONE HETEROATOM SELECTED FROM THE GROUPCONSISTING OF OCYGEN, SULFUR, CHLORINE, BROMINE AND NITROGEN, SAIDHETEROATOM BEING IN AN ACYCLIC LINKAGE, TO FORM A DIFFERENT COMPOUNDCONTAINING A CARBONYL GROUP SELECTED FROM THE GROUP CONSISTING OFALDEHYDE AND KETO CARBONYL GROUPS WHICH COMPRISES INTIMATELY CONTACTINGSAID COMPOUND CONTAINING AT LEAST ONE OLEFINICALLY UNSATURATED BOND WITHAN AQUEOUS SOLUTION OF A PLATINUM GROUP METAL SALT AT A TEMPERATURE OFABOVE 0*C. TO ABOUT 250*C.